标签：swift语言学习
最近参照Swift文档 和 http://www.chinaz.com/swift/chapter1/02_a_swift_tour.html的学习整理
//
// main.swift
// TestSwift1
//
// Created by zql on 14-9-10.
// Copyright (c) 2014年 TU. All rights reserved.
//
import Foundation
println("Hello, World!")
println("Hello Swift")
var myVariable = 42
myVariable = 50//var 声明变量 类型编译器自己判定
let myConstant = 42//let 声明常量 类型编译器自己判定
let implicitInteger = 70
let implicitDouble = 70.0
let exPlicitDouble:Double = 70 //如果需要指明变量类型，则如此类写法
//类型转换
let label = "The width is "
let width = 94
let labelWidth = label + String(width)
println(labelWidth) //值永远不会被隐式转换为其他类型。如果你需要把一个值转换成其他类型，请显式转换。
//有一种更简单的把值转换成字符串的方法：把值写到括号中，并且在括号之前写一个反斜杠
let apples = 3
let oranges = 5
let appleSummary = "I have \(apples) apples"
let orangeSummary = "I have \(oranges) oranges"
println(appleSummary + "\n" + orangeSummary)
let h = 1.78
let description = "Your h is \(h)"
println(description)
//创建数组和字典
var shopList = ["catfish","water","apple"]//创建数组
shopList[0] = "you and me"//访问数组
var personInfo = [
"name":"zhang",
"age":"24",
]//创建字典
personInfo["name"] = "M"//使用key访问字典
personInfo["sex"] = "nan"//动态添加key-value
let emptyAry = String[]()//创建空数组
let emptyDic = Dictionary<String,Float>()//创建空字典对象
//控制流
let individualScores = [75,43,103,87,12]
var teamScore = 0
//使用for-in循环
for score in individualScores
{
if score > 50
{
teamScore += 3
}
else
{
teamScore += 1
}
}
println("The teamScore is \(teamScore)")
/*
在if语句中，条件必须是一个布尔表达式——这意味着像if score { ... }这样的代码将报错，而不会隐形地与 0 做对比。
你可以一起使用if和let来处理值缺失的情况。有些变量的值是可选的。一个可选的值可能是一个具体的值或者是nil，表示值缺失。在类型后面加一个问号来标记这个变量的值是可选的。
*/
var optionalString :String? = "Hello" //表示变量值可选
optionalString = nil
var optionalName:String? = "Zhang"
var greeting = "Hello!"
if let nameStr = optionalName //nameStr 不是nil
{
greeting = "Hello,\(nameStr)"
}
println(greeting)
optionalName = nil
if let nameStr = optionalName //nameStr 不是nil
{
greeting = "Hello,\(nameStr)"
}
println(greeting)
/*
switch支持任意类型的数据以及各种比较操作——不仅仅是整数以及测试相等。
运行switch中匹配到的子句之后，程序会退出switch语句，并不会继续向下运行，所以不需要在每个子句结尾写break
*/
let vegetable = "red pepper"
switch vegetable
{
case "celery":
let vegetabelComment = "Add some raisins and make ants on a log"
case "cucumber", "watercress":
let vegetableComment = "That would make a good tea sandwich."
case let x where x.hasSuffix("pepper"):
let vegetableComment = "Is it a spicy \(x)?"
default:
let vegetableComment = "Everything tastes good in soup."
}
//使用for-in 来遍历字典
let interestingNumbers = [
"prime":[2,3,4,5,7,11,13],
"Fibonacci": [1, 1, 2, 3, 5, 8],
"Square": [1, 4, 9, 16, 25],
]
var largest = 0
for (key,values) in interestingNumbers
{
for number in values
{
if number > largest
{
largest = number
}
}
}
//使用while and do-while
var n = 2
while n < 100
{
n = n*2
}
println("n is \(n)")
var m = 2
do
{
m = m*2
}while m < 100
println("n is \(m)")
//可以在循环中使用..来表示范围，也可以使用传统的写法，两者是等价的 使用..创建的范围不包含上界，如果想包含的话需要使用...
var firstForLoop = 0
for i in 0..3
{
firstForLoop += i
}
println("firstForLoop is \(firstForLoop)")
var secondForLoop = 0
for var i = 0;i < 3; i++
{
secondForLoop += i
}
println("secondForLoop is \(secondForLoop)")
//函数和闭包
//使用func来声明一个函数，使用名字和参数来调用函数。使用->来指定函数返回值
func greet(name:String,day:String)->String
{
return "Hello \(name),today is \(day)"
}
println(greet("Boob","3"));
//使用一个元组来返回多个值
func getGasPrices()->(Double,Double,Double)
{
return (3.59,1.78,3.79)
}
println(getGasPrices())
//函数的参数数量是可变的，用一个数组来获取它们
func sumOf(numbers:Int...)->Int
{
var sum = 0
for number in numbers
{
sum += number
}
return sum
}
println(sumOf())
println(sumOf(1,2,3))
//函数可以嵌套。被嵌套的函数可以访问外侧函数的变量，你可以使用嵌套函数来重构一个太长或者太复杂的函数。
func returnFifteen()->Int
{
var y = 10
func add()
{
y += 5
println("###########")
}
add()
println("······###########·····")
return y
}
returnFifteen()
//函数可以作为另一个函数的返回值。
func makeIncrementer()->(Int->Int)
{
func addOne(number:Int)->Int{
return 1+number
}
return addOne
}
var increment = makeIncrementer()
increment(7)
println(increment(7))
//函数也可以当做参数传入另一个函数。
func hasAnyMatches(list:Int[],condition:Int->Bool)->Bool
{
println("······-------·····")
for item in list
{
if condition(item)
{
println("······========·····")
return true
}
}
return false
}
func lessThanTen(number:Int)->Bool
{
println("······;;;;;;;·····")
return number<10
}
var number = [20,19,7,29]
hasAnyMatches(number,lessThanTen)
标签：swift语言学习
原文地址：http://zqlicoder1314.blog.51cto.com/3014999/1550430
